WP 6.6 RC 3: Block global styles in the site editor become stuck on the site frontend

[andrewserong]

Description

Tracked in core in https://core.trac.wordpress.org/ticket/59595#comment:71 — note this is an issue in core, and not the Gutenberg repo. It's added here for visibility as it relates to behaviour with global styles in the site editor.

It looks like the caching strategy in WP 6.6 has resulted in a regression where the styles for blocks in global styles become stuck on the site frontend when a user goes to make updates to the styles for a block within global styles.

Step-by-step reproduction instructions

1. Open the site editor on a WP 6.6 RC3 site running Twenty Twenty Four theme (without Gutenberg activated)
2. Click the editor preview to go into edit mode
3. Open the Global Styles sidebar panel on the right hand side
4. Click Blocks
5. Select the Button block
6. Give the Button block a style, e.g. Background color set to a gradient
7. Save the global styles
8. Load the site frontend — notice that the styling on the Button is applied
9. Go back to global styles and give the Button block another style, e.g. large font size
10. Save the global styles
11. Load the site frontend and notice that the Button block's styling has not changed — it'll be cached with the previous styles that were originally saved

Screenshots, screen recording, code snippet

2024-07-12.15.25.08.mp4

Environment info

• WP 6.6 RC 3
• Gutenberg is not active. This issue does not appear to occur in Gutenberg.

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[andrewserong]

There is a potential draft fix open over in: WordPress/wordpress-develop#7017

[andrewserong]

Closing this out now as the change that introduced the regression has been reverted in core. See: https://core.trac.wordpress.org/ticket/59595#comment:84